Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The troponin I peptide N alpha-acetyl TnI (104-115) amide (TnIp) represents the minimum sequence necessary for inhibition of actomyosin ATPase activity of skeletal muscle (Talbot, J.A. & Hodges, R.S. 1981, J. Biol. Chem. 256, 2798-3802; Van Eyk, J.E. & Hodges, R.S., 1988, J. Biol. Chem. 263, 1726-1732; Van Eyk, J.E., Kay, C.M., & Hodges, R.S., 1991, Biochemistry 30, 9974-9981). In this study, we have used 1H NMR spectroscopy to compare the binding of this inhibitory TnI peptide to a synthetic peptide heterodimer representing site III and site IV of the C-terminal domain of troponin C (TnC) and to calcium-saturated skeletal TnC. The residues whose 1H NMR chemical shifts are perturbed upon TnIp binding are the same in both the site III/site IV heterodimer and TnC. These residues include F102, I104, F112, I113, I121, I149, D150, F151, and F154, which are all found in the C-terminal domain hydrophobic pocket and antiparallel beta-sheet region of the synthetic site III/site IV heterodimer and of TnC. Further, the affinity of TnIp binding to the heterodimer (Kd = 192 +/- 37 microM) was found to be similar to TnIp binding to TnC (48 +/- 18 microM [Campbell, A.P., Cachia, P.J., & Sykes, B.D., 1991, Biochem. Cell Biol. 69, 674-681]). The results indicate that binding of the inhibitory region of TnI is primarily to the C-terminal domain of TnC. The results also indicate how well the synthetic peptide heterodimer mimics the C-terminal domain of TnC in structure and functional interactions.
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PMID:A 1H NMR study of a ternary peptide complex that mimics the interaction between troponin C and troponin I. 130 91

Autophosphorylation of a soluble approximately 48-kDa derivative of the insulin receptor protein-tyrosine kinase is accompanied by an increase in its specific activity towards exogenous substrates. In the present study, we have utilized 1H NMR to compare the order and rate of mono- and diphosphorylation of multiple tyrosine residues in a series of synthetic dodecapeptide substrates (based on the receptor sequence, which includes major sites of autophosphorylation (RRDIYETDYYRK), with substitution(s) at positions 6 and/or 7 based on residue size and/or charge) by the approximately 48-kDa enzyme and by a approximately 38-kDa enzyme generated by tryptic deletion of approximately 10 kDa from the carboxyl terminus of the approximately 48-kDa protein. Both enzymes exhibit a marked order and progression of phosphorylation of peptide tyrosine residues; for each peptide, phosphorylation initiates and proceeds to completion first on tyrosine 9, followed by phosphorylation on tyrosine 10. Although removal of the carboxyl terminus does not affect the rate of monophosphorylation of these peptides on tyrosine 9, the smaller enzyme exhibits a slower rate of diphosphorylation (at tyrosine 10), as compared with the approximately 48-kDa enzyme.
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PMID:Deletion of approximately 10 kDa from the carboxyl terminus of a soluble approximately 48-kDa insulin receptor protein-tyrosine kinase results in slower rates of diphosphorylation of a series of dodecapeptide substrates. An assessment by 1H NMR. 164 94

Autophosphorylation of a soluble approximately 48-kDa derivative of the insulin receptor protein-tyrosine kinase occurs at multiple tyrosine residues (analogous to tyrosines 1158, 1162, and 1163 in the kinase homology region of the native receptor and tyrosines 1328 and 1334 in the carboxyl-terminal tail) and is accompanied by an increase in the specific activity of the enzyme toward exogenous substrates. A comparison of 1H NMR spectra of approximately 48- and approximately 38-kDa forms of enzyme (the latter generated by tryptic deletion of approximately 10 kDa from the carboxyl terminus of the approximately 48-kDa protein) allows a correlation of observed mobile tyrosine resonances to two of the known sites of autophosphorylation (residues 1328 and 1334). Furthermore, spectra acquired during autophosphorylation of the approximately 48-kDa enzyme reveal a rapid downfield shift in the resonances of these mobile tail tyrosines consistent with their phosphorylation (as confirmed by two-dimensional tryptic phosphopeptide mapping performed under identical conditions). This experimental strategy now provides a means by which to monitor protein-tyrosine kinase autophosphorylation in solution in real time.
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PMID:Autophosphorylation of soluble insulin receptor protein-tyrosine kinases. 1H NMR spectral changes observed during phosphorylation of mobile tyrosine residues. 164 90

31P NMR spectroscopy was used to study the time course of changes in the concentration of high-energy metabolites and intracellular pH in the dog myocardium during hypothermic ischaemia at 9 degrees C in Bretschneider (HTK-B) and St. Thomas' Hospital (StTH) cardioplegic solutions. It was found that ATP and phosphocreatine degrade slowlier in HTK-B than in StTH, with phosphocreatine depletion occurring within 7.9 +/- 1.4 h in HTK-B and within 6.2 +/- 1.4 h in StTH. The values are virtually identical with the time intervals at which ATP concentration falls below the critical level (60% of initial ATP concentration). In agreement with biochemical analysis, a higher concentration of phosphomonoesters was noted until the 180th minute of ischaemia in HTK-B, a finding suggesting more rapid glycogen degradation in HTK-B. Even though HTK-B contains a high concentration of histidine buffer, higher values of intracellular pH were found during ischaemia in StTH. The effect of extracellular concentration of sodium ions on intracellular pH is discussed.
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PMID:The phosphate pool of isolated dog heart during global ischaemia: comparison of two cardioplegic solutions with 31P NMR spectroscopy. 181 21

A conformational analysis has been performed on several peptide fragments (CCK4 to CCK7) of the cholecystokinin neuromodulator. The Monte-Carlo Metropolis method was used to explore the conformational space of all these flexible units and different electric charge distributions were introduced in order to mimic pH effects. Results agree reasonably well with experimental data from NMR and fluorescence experiments. The CCK4 fragment displays a peculiar conformational behavior when compared to all other longer peptides with short range interaction between the Trp and Phe aromatic side-chains. Several H-bonded conformers including C- or beta-turns are found for CCK5 to CCK7. These findings are correlated to the central and peripheral actions of these compounds and hypotheses concerning the best possible templates for each one are discussed.
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PMID:Computational analysis of conformational behavior of cholecystokinin fragments. I-CCK4, CCK5, CCK6 and CCK7 molecules. 191 99

To assess the performance of FLAG and RSE NMR angiography 22 aortoiliac (AI) and 22 femoropopliteal (FP) angiograms in 11 healthy males, mean age 38 +/- 7.6 years, were acquired. The image quality was graded in a blinded fashion by two independent readers. The readers grades were not statistically different (kappa = 0.5696). The representation of diagnostic images was 6/11 FLAG and 8/11 RSE AI as well as 8/11 FLAG and 8/11 RSE FP. On back-to-back comparison six RSE AI and seven RSE FP were graded better than their FLAG counterparts. Although these differences did not achieve a statistical significance RSE NMR angiography provided consistently better images and appears preferable for imaging of the peripheral vascular system in normal subjects.
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PMID:Aortoiliac and femoropopliteal phase-based NMR angiography: a comparison between FLAG and RSE. 223 17

Four tissue compartments, differing in proton and inorganic phosphate concentration, were resolved by 31P-NMR spectroscopy in samples from dog hearts after cardioplegic treatment with HTK solution. Inversion of the physiological cytoplasmic-mitochondrial pH gradient was observed. The considerable ensuing acidosis of the matrix is discussed with regard to a possible delocalization of ferrous ions.
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PMID:31P-NMR spectroscopy of phosphate compartmentation during ischaemia in hearts protected by cardioplegic treatment. 251 Oct 87

Three serotransferrin variants Tf 2a, Tf 4b and Tf 5b were isolated in an homogeneous form from a preparation of homozygous horse serotransferrin Tf 0. On the basis of the results concerning molecular mass determination and the carbohydrate analysis, it is concluded that the serotransferrin variant Tf 2a contains only one glycan while variants Tf 4b and Tf 5b contain two glycans. The structure of all of the glycans has been established by combining methylation analysis, mass spectrometry and 400-MHz 1H-NMR spectroscopy. From the obtained results, it appears that the two glycans of Tf 5b variant are, like in human serotransferrin, of the N-acetyllactosaminic biantennary type, fully sialylated by two residues of N-acetylneuraminic acid (Neu5Ac; glycan type I). In contrast, in addition to this structure, two N-acetyllactosaminic biantennary isomeric structures named type II-A and type II-B sialylated by one Neu5Ac residue and one N-acetyl-4-O-acetylneuraminic acid [Neu(4,5)Ac2] residue located either at Gal6 or 6' and one N-acetyllactosaminic biantennary structure (named type III) sialylated by two residues of Neu(4,5)Ac2, were identified in variants Tf 2a and Tf 4b. These results demonstrate that in an homozygous preparation of horse serotransferrin Tf 0, the heterogeneity is dependent, on the one hand, on the nature of the neuraminic acid substituting a N-acetyllactosaminic biantennary structure and, on the other hand, on the number of glycans bound to the polypeptide chain. Moreover, the differences which exist in the molecular mass of 77.5 kDA, 80 kDa and 82 kDa for serotransferrin variants Tf 2a, Tf 4b and Tf 5b, respectively, are not completely explained by the structure and the number of the glycans suggesting that the three variants should also differ in their polypeptide chain.
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PMID:Primary structure of horse serotransferrin glycans. Demonstration that heterogeneity is related to the number of glycans and to the presence of N-acetylneuraminic acid and N-acetyl-4-O-acetylneuraminic acid. 260 6

Carbon-13 NMR spectroscopic studies of native and sequentially deglycosylated ovine submaxillary mucin (OSM) have been performed to examine the effects of glycosylation on the conformation and dynamics of the peptide core of O-linked glycoproteins. OSM is a large nonglobular glycoprotein in which nearly one-third of the amino acid residues are Ser and Thr which are glycosylated by the alpha-Neu-NAc(2-6)alpha-GalNAc- disaccharide. The beta-carbon resonances of glycosylated Ser and Thr residues in intact and asialo mucin display considerable chemical shift heterogeneity which, upon the complete removal of carbohydrate, coalesces to single sharp resonances. This chemical shift heterogeneity is due to peptide sequence variability and is proposed to reflect the presence of sequence-dependent conformations of the peptide core. These different conformations are thought to be determined by steric interactions of the GalNAc residue with adjacent peptide residues. The absence of chemical shift heterogeneity in apo mucin is taken to indicate a loss in the peptide-carbohydrate steric interactions, consistent with a more relaxed random coiled structure. On the basis of the 13C relaxation behavior (T1 and NOE) the dynamics of the alpha-carbons appear to be unique to each amino acid type and glycosylation state, with alpha-carbon mobilities decreasing in the order Gly greater than Ala = Ser greater than Thr much greater than monoglycosylated Ser/Thr approximately greater than disaccharide linked Ser/Thr.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of glycosylation on the conformation and dynamics of O-linked glycoproteins: carbon-13 NMR studies of ovine submaxillary mucin. 277 22

For the first time, an oligosaccharide has been prepared comprising the lipid A backbone, the core oligosaccharide and one repeating unit of the O-specific polysaccharide (O-chain) of a lipopolysaccharide. Lipopolysaccharide from Vibrio cholerae strain H11 (non-O1) was deacylated and the products were separated by high-performance anion-exchange chromatography. Major fractions were a hexadecasaccharide trisphosphate 1, representing the core-lipid A oligosaccharide substituted by one modified repeating unit of the O-antigenic polysaccharide, a dodecasaccharide trisphosphate 2 and an undecasaccharide trisphosphate 3, representing the core-lipid A region. Oligosaccharide 1 originated from beta-elimination upon alkaline hydrolysis of alpha-galacturonic acid of the O-chain; oligosaccharides 2 and 3 were most likely obtained from naturally occurring lipopolysaccharide species carrying no O-chain. The structures of these compounds were elucidated on the basis of monosaccharide composition, and NMR investigations comprising correlation spectroscopy, total correlation spectroscopy and nuclear Overhauser enhancement spectroscopy experiments, as well as heteronuclear 13C, 1H correlation spectroscopy. The structures are as follows: [formula: see text] where R is beta-L-threo-hex-4-enuronopyranosyl-(1-4)-alpha-Neu-(2-3)-beta-Gal A-(1-3)- beta-QuiN-(1-4)-beta-Sedf-(2- in 1, beta-Sedf-(2- in 2, and H in 3. Where not stated otherwise, sugars are pyranoses of the D-series. Hep is L-glycero-D-manno-heptose, QuiN is 2-amino-2,6-dideoxy-glucose, Kdo is 3-deoxy-D-manno-2-octulosonic acid, Sed is D-altro-heptulose and GalA is galacturonic acid.
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PMID:Isolation and structural analysis of oligosaccharide phosphates containing the complete carbohydrate chain of the lipopolysaccharide from Vibrio cholerae strain H11 (non-O1). 752 84


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